Introduction to Database
1.0 Introduction
Database is a collection of related data. Database management system is software
designed to assist the maintenance and utilization of large scale collection of data. DBMS
came into existence in 1960 by Charles. Integrated data store which is also called as the
first general purpose DBMS. Again in 1960 IBM brought IMS-Information management
system. In 1970 Edgor Codd at IBM came with new database called RDBMS. In 1980
then came SQL Architecture- Structure Query Language. In 1980 to 1990 there were
advances in DBMS e.g. DB2, ORACLE.
Data
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Data is raw fact or figures or entity.
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When activities in the organization takes place, the effect of these activities need
to be recorded which is known as Data.
Information
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Processed data is called information
The purpose of data processing is to generate the information required for
carrying out the business activities.
In general data management consists of following tasks
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Data capture: Which is the task associated with gathering the data as and when
they originate.
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Data classification: Captured data has to be classified based on the nature and
intended usage.
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Data storage: The segregated data has to be stored properly.
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Data arranging: It is very important to arrange the data properly
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Data retrieval: Data will be required frequently for further processing,
Hence it is very important to create some indexes so that data can be retrieved
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easily.
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Data maintenance: Maintenance is the task concerned with keeping the data upto-date.
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Data Verification: Before storing the data it must be verified for any error.
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Data Coding: Data will be coded for easy reference.
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Data Editing: Editing means re-arranging the data or modifying the data for
presentation.
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Data transcription: This is the activity where the data is converted from one form
into another.
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Data transmission: This is a function where data is forwarded to the place where it
would be used further.
Metadata (meta data, or sometimes meta information) is "data about data", of any sort
in any media. An item of metadata may describe a collection of data including multiple
content items and hierarchical levels, for example a database schema. In data processing,
metadata is definitional data that provides information about or documentation of other
data managed within an application or environment. The term should be used with
caution as all data is about something, and is therefore metadata.
Database
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Database may be defined in simple terms as a collection of data
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A database is a collection of related data.
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The database can be of any size and of varying complexity.
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A database may be generated and maintained manually or it may be computerized.
Database Management System
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A Database Management System (DBMS) is a collection of program that enables
user to create and maintain a database.
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The DBMS is hence a general purpose software system that facilitates the process
of defining constructing and manipulating database for various applications.
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1.1
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Characteristics of DBMS
To incorporate the requirements of the organization, system should be designed
for easy maintenance.
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Information systems should allow interactive access to data to obtain new
information without writing fresh programs.
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System should be designed to co-relate different data to meet new requirements.
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An independent central repository, which gives information and meaning of
available data is required.
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Integrated database will help in understanding the inter-relationships between data
stored in different applications.
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The stored data should be made available for access by different users
simultaneously.
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Automatic recovery feature has to be provided to overcome the problems with
processing system failure.
DBMS Utilities
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A data loading utility:
Which allows easy loading of data from the external format without writing
programs.
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A backup utility:
Which allows to make copies of the database periodically to help in cases of
crashes and disasters.
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Recovery utility:
Which allows to reconstruct the correct state of database from the backup and
history of transactions.
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Monitoring tools:
Which monitors the performance so that internal schema can be changed and
database access can be optimized.
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